Heretofore, it has been known that alkylated sugars are useful as surfactants, and for this reason, the sugars employed as the raw materials have been limited to inexpensive ones. The prior art documents related to the alkylated sugars include: U.S. Pat. No. 3,219,656; U.S. Pat. No. 3,547,828; U.S. Pat. No. 3,839,318; Japanese Pat. Application First Publication No. 58-194901; B. W. LEW et al, J. Am. Oil. Chem. Soc. vol. 47, 163-167 (1970); and the like. These prior art documents pertain to glycosides which are products obtained from reactions between monosaccharides and alcohols. In these prior art documents, although it is disclosed that a small amount of the products obtained from the reactions between the alcohols and the oligosaccharide mainly produced by self-polymerization-reacting the sugars is by-produced, there are no descriptions about the structures, and stereo-and regio- chemistries of the by-product oligosaccharides.
In addition, the oligosaccharides employed as the raw materials of the present invention can be produced by various conventional methods for manufacturing the same. For example, .beta.(1.fwdarw.3) oligoglucose can be produced by decomposition of curdlan, laminarane or the like using the enzyme produced by microorganism belonging to the group Streptomyces, or by acid decomposition of curdlan, laminarane or the like.
In addition, a galactose type oligosaccharide having a lactose moiety, .beta.-D-galactosyl-.beta.(1.fwdarw.4)-D-galactosyl-.beta.(1.fwdarw.4)-D-g lucose can be produced by the method disclosed in A. Ballio et al. (Tetrahedron, 9, 125, 1960), J. H. Pazur et al. (J. Am. Chem. Soc., 80, 119, 1958), J. G. Collins et al. (Carbohydr. Res., 92, 136, 1981), or Japanese Pat. Application First Publication No. 2-79992 filed by the present applicants. In addition, .beta.-D-galactosyl-.beta.(1.fwdarw.4)-D-galactosyl-.beta.(1.fwdarw.4)-D-g alactosyl-.beta.(1.fwdarw.4)-D-glucose and the like can be produced by the methods disclosed in Japanese Patent Application First Publication No. 60-251896 filed by the present applicants.
However, in the documents described above, there is no description of an alkylated oligosaccharide wherein the oligosaccharide described above is alkylated, nor is a method for producing the same disclosed.
In addition, a number of reports have recently been published wherein the polysaccharide sulfates are useful as the medical agents for Acquired Immune Deficiency Syndrome (AIDS). For this reason, the sulfates of polysaccharides have attracted much attention.
However, these polysaccharides have several disadvantages. They have a strong tendency to act as an anticoagulant, and are difficult to administer due to their poor absorption within a living organism because of molecular weight in excess of ten thousand or more.
It is an object of the present invention to provide a novel alkylated oligosaccharide and the acetyl derivative of the same, having low decomposition properties in a living organism, and which are useful as the raw materials for producing medicines having improved absorption in a living organism.